Boat tail vs flat base

[No4Mk1*]

Looking at a few ballistics charts, it seems like most hunting ammo is not loaded with boat tail bullets. I'm curious as to why if this is true. Why waste enery when it seems so simple to use an aerodynamic bullet?

Comparing 180grain 30 caliber loads at 300 yards...
Flat base bullets:
.308 - 1970 ft/sec
.30-06 - 2040 ft/sec
.300WinM- 2220 ft/sec

Boat tails:
.308 - 2117 ft/sec
.30-06 - 2220 ft/sec
.300WinM- 2344 ft/sec

 

[Preacherman]

But most such ammo is shot at way less than 300 yards - in fact, I'd hazard a guess that the "average" game shot in the US is at less than 100 yards. The boat-tail bullet configuration has no advantage at short ranges, and only comes into its own over longer distances. So, if 80%-plus of shots are at short ranges, why use long-range bullets for them?

 

[rbernie]

Evidently, getting a consistant taper to the boat tail can be difficult to do cheaply, and the price of getting it wrong is having a bullet that 'wobbles' too long in flight and doesn't settle down and 'fly right'. Therefore, hunting-quality flat base bullets can be made mo' cheaply and can actually be more accurate than their boat tail counterparts.

 

[No4Mk1*]

I didn't think about it being more expensive to make the bullets. Thanks.

 

[Ol` Joe]

Boat tails unless "bonded cored" are also more apt to shed their jackets then flat base. Flat base designs are also usually more accurate at shorter range then the BT. The short range bench shooters almost all win with flat base designs. The BT accuracy comes in at longer range ~600+yds) where the velocity drops below the speed of sound and wind drift becomes a bigger factor.

The ballistics are a bit less dramatic then you picture also. Take the same wgt 180gr 30 cal bullets as you used, one a soft point the other a boat tail, both made by Speer. With a starting velocity of 2600 fps useing the Lee balistic program we get....

180gr SP @ 2600 fps
300 yd drop with a 200 yd zero = 8.90"
300 yd energy = 1743fp

180gr SPBT @ 2600 fps
300 yd drop with 200 yd zero = 9.39"
300 yd energy = 1588fp

This translates into .49" less drop and 155 fp less energy at 300 yds for the flat base bullet. This along with a more dependable/accurate design make a FB bullet as good or better for most hunting. The velocity and bullet is a std loading in the `06 but the numbers will hold very close if the same two bullets are compared in other 30 cal cartridges.

 

[Sharps Shooter]

Practical, real world experience causes me to agree with every responce so far. I've used Hornady 165 grain boat tails in my 30-06 for deer hunting for a good many years. But where we hunt, shots are often 150 yards plus. I once shot a mule deer in the thorax from an honest to goodness 420 yards away (I was resting the rifle in the crotch of a tree). That boat tail went the length of his body and lodged in his left hip. It had over 90% weight retention. But the thing is, that deer was a long ways off. The bullet had slowed conciderably when it struck. On the other hand, occasionally I'll get a shot at a deer at 75 yards or less. Those results are almost always the same. Sure, it's a dead deer, but the boat tail sheds it's jacket and I find little pieces of it's lead core strewn all over in the deers shoulder muscles and ribs.
As far as accuracy goes, my 30-06 will put 3 of those Hornady boat tails in an inch at 100 yards. But my wife's 7mm-08 absolutely hates Hornady boat tails. We went through 2 boxes of Hornady 7mm, 139 grain boat tails trying to get them to put 3 in less than 4 inches at 100 yards. We switched to Hornady 139 grain plain base and problem solved - her 7mm-08 is as accurate as any rifle we have. We simply quit worrying about the one or two inches of flatter trajectory at 400 yards. If your group is 1" at 100 yards, you might hit 4" high at 400 yards anyway. And a 150 more foot pounds of energy really doesn't mean anything provided you hit the animal with enough power to humanely take him in the first place.

 

[Art Eatman]

Inside 300 yards, the differnce in aerodymanics is negligible.

The Sierra folks told us one time, back at the first TFL daze, that the 150-grain .308 BT had a bit thinner jacket than the flat base, and fragmented rather quickly if driven to above 2,800 ft/sec at impact.

I've used the SPBT Sierra and been quite happy, but most of my shots with my '06 have been at longer ranges than is common.

As usual, the design you pick depends on how you're gonna use it...

 

[Gewehr98]

That doesn't mean there aren't boattail hunting bullets...

For example, the Nosler Ballistic Tips, and Sierra GameKings.

But even the 200-yard benchresters use flat-base bullets, because they don't need the retained velocities offered by the boattails when the target is that close. That, and a boattail base increases the chances of off-axis muzzle departure unless it's done properly. One fix to this problem is the rebated boattail, as sold by Lapua.

I've used boattail hunting bullets out to 600 yards on antelope-sized game. The energy retention is a nice thing, as is the accuracy potential. For your average deer-getter and the ranges he connects with the venison, a flat-base hunting bullet will do quite nicely.

Those long-range varmint hunters, and paper-punchers, all the way out to 1000 yards and then some, can and do take advantage of the boattail bullet design, however.

 

[Tony Williams]

Agree with responses so far. The boat-tailed bullet was a military invention, designed to extend the range of machine guns used in area fire. It does in fact have quite a dramatic effect at extremely long range, once the bullet has dropped into the subsonic range.

I suspect that most commercial BT hunting bullets have adopted the form because it's associated with superior performance in people's minds - rather like the belted case on a magnum.

TW

 

[Dr. J Frame]

While browsing Benchrest Central I once read that no national competition had been won with a boattail at 300yds or less. Some posters claimed the yaw of the boattail was adversly affected within the first few millimeters upon exit of the barrel, while flatbased bullets do not encounter this.

Of course, this is something I read ON THE INTERNET.

 

[Vern Humphrey]

Boat tails unless "bonded cored" are also more apt to shed their jackets then flat base. Flat base designs are also usually more accurate at shorter range then the BT.

I have seen respected gun writers claim that boat tails come apart on game, and that they don't -- and both back it up with statistical accounts of many head of game shot with both boat tails and flat bases.

My own experience and that of a few of my friends is that boat tails DO tend to come apart in game. I once shot a running white tail with a .30-06, he went down and came back up, went down at the second shot, bounced up again, and it took a third shot to put him down permanently.

The first shot was a perfect quartering away shot from the right. The bullet struck the deer in the flank, angled forward, and came apart. I found the jacket lodged against the leg bone -- it should have broken that bone.

The second shot was a mirror image, but this time the deer was quartering the other way. Again, the bullet angled forward, and the jacket was found lodged against the opposite leg bone. The third shot was broadside, and the bullet was not recovered.

A friend had an almost identical experience on a 450-lb black bear, which he finished off with a .357.

Also, the base of the bullet is the most critical part for accuracy -- you can deliberately deform bullet noses and shoot good groups. But mess with the base, and kiss accuracy good bye. A good flat base will therefore be more accurate than a medeocre boat tail.

For a hunter, the only advantage of a boat tail that I see is that they are easier to hand load -- the boat tail allows you to seat them firmly in the case by hand before you run them up into the seating die.

 

[Peter M. Eick]

There is the aerodynamic question and then there is an accuracy question. It is easier to make an accurate bullet with fewer bends in it from what I have read. Making a good quality, accurate boat tail is hard to do. Call up the seirra tech line and talk to them about it. They explained to me that getting the boat tail perfect is hard to do for the Matchking series and the issue is when the bullet leaves the barrel, any errors in the boat tail cause problems and instabilities. A flat base is easier to achieve good accuracy with. This is also why a good muzzle crown is so important.

I suggest again you call seirra and chew the topic over with them. They are very helpful.